This invention relates to a process for making an ingredient useful in the production of snack foods. The ingredient is made from whole cereal grains which are ground prior to hydration and gelatinization of starch in the grain. The resulting product can be used as a snack food ingredient in a number of processes, as for instance a sheeted and fried corn chip product.
The present invention contemplates the use of one, or a combination of, starch-containing grains, such as corn, wheat, barley, oats, rye or rice as the basis of the snack food ingredient. Because of the large existing market for corn-based snack foods, the invention herein will be described primarily with reference to corn as the base material for the ingredient, but it should be recognized that the process works equally well for any mixture of the other named grains.
Conventional corn chips used as snack foods utilize a process wherein whole corn kernels are cooked and later soaked in hot lime water until the kernels have been completely penetrated by the hot alkaline solution and the kernel has become softened and the hulls partially digested. The lime treatment is required to soften and digest the hemi-cellulose content of the hulls and to alter the protein content of the kernel so that the hull can be removed by washing and the kernel readily disintegrated by stone grinding or other conventional grinding methods. This conventional process, still widely in use in the snack food industry, is wasteful from both a nutritional and process yield standpoint, in that the lime treatment extracts inter alia thiamine, riboflavin and niacin, and a significant portion of the total corn solids are lost in the water used to wash off the softened hull. While such products are acceptable to a great many people, a substantial portion of the population experiences an undesirable aftertaste resulting from the lime treatment. Countries of the western hemisphere are apparently the only ones in which this "Mexican" flavor is not objectionable; in most of Europe and the Far East such snacks have not gained acceptance because this flavor is perceived by most people as unpalatable.
Additionally, the corn ingredient or "masa" made by the conventional manufacturing process does not give a corn ingredient with uniform properties for snack processing. I have found that conventional corn processing leaves unsoftened portions of corn tissue in the center of the corn kernels. These portions have a lower moisture content, and therefore the starch is less gelatinized than in the outer more hydrated portions of the kernels. This random consistency within the corn kernel results in a ground cooked corn ingredient containing relatively large hard particles that cause a "gritty" mouthfeel in the finished snack product. While this "gritty" texture authentically recreates the traditional Mexican snack, it is objectionable to many people who prefer the smooth texture of, for instance, potato chips.
There have been a number of attempts to alter these and other deficiencies in the conventional process of corn chip manufacture. In U.S. Pat. No. 3,404,986, a process is disclosed whereby a portion of standard meal (a mixture of finely divided portions of corn germ and endosperm) and degerminated meal are blended at a moisture content of 16-35% and permitted an aging time of approximately one-half hour. A desired level of starch gelatinization is obtained by passing the hydrated mixture through the nip of rolls heated to 275.degree.-500.degree. F. These heated rolls serve not only to gelatinize the starch, but also to inactivate enzymes responsible for rancidity. Thereafter, the corn meal containing partially gelatinized starch is comminuted and used in the production of tortillas.
A long shelf life flour is produced by the process of U.S. Pat. No. 4,089,259, wherein whole grains are heated before comminution in order to deactivate enzymes which might cause rancidity. The process disclosed therein comprises adding surface water to kernels of grain which are fed into a roaster, which upon leaving the roaster are squeezed into flat flakes between heated (180.degree.-300.degree. F.) rollers. The heated rollers raise the temperature of the flakes to above 170.degree. F., which are thereafter cooled and hammer milled into flour-sized particles.
Puffed fried food products, are made either directly in-process or from shelf stable pellets, by the process disclosed in U.S. Pat. No. 3,800,050. In this process, a dilute mixture of a high setback starch and water is mixed with one or more whole grains which may have been previously soaked in water and ground, or dry ground, and then heated to above the gelatinization point of the starch. The cooked, gelatinized mixture is then extruded as a thin layer of gel onto a cooling belt with air directed over the extrudate. A "skin" of gelatinized starch is said to develop on the surface of the extruded material which aids in the entrapment of steam within the product when it is subsequently fried. The thin layer of gel is then cut into rectangular shapes and dried to a stable moisture content of about 10% to form a pellet or "half-product". Subsequent frying of the pellets may take place immediately or the dried product may be stored for later use.
A manufactured or fabricated corn chip product of uniform shape is disclosed in U.S. Pat. No. 3,132,949, wherein a whole grain, such as corn is conventionally cooked in lime water and then stone ground until masa results. This masa is extruded in ropes and cut into individual pieces which are thereafter constrained between a pair of conveyors in an oven which flattens and partially precooks the pieces to a rubber-like consistency. These flattened pieces are somewhat less dense than cooking oil and therefore float. When subsequently immersed in hot cooking oil, these pieces float upwardly and contact a moving belt having caternary curves which form the pieces into the desired shape. Other patents of interest, but of less relevance, include U.S. Pat. Nos. 2,704,257, 3,545,979, and 3,708,308.
Therefore, it is an object of the present invention to provide a whole grain ingredient with no loss of fiber-containing solids which does not have the lime flavor of conventional chip products. Additionally, the process is intended to provide a snack food having a uniform texture upon eating, with this uniform texture being somewhat more tender than conventional snack food products.
Finally, the process is intended to provide a snack food free from relatively large non-uniformly ground and cooked particles readily perceived as "gritty" by those consuming the snacks.